Benthic communities in floodplain lake ecosystems are often exposed to varying levels of both food and toxicants. Inhibition through toxicants of sensitive species and stimulation through increased amounts of food of opportunistic species have been observed in separate studies. The aim of this study was therefore to assess the responses ...

The Mersey estuary is the most contaminated estuary in British waters. Detailed studies are underway on the pathology of flounder (Platichthys flesus) from the Mersey and on flounder from the nearby, but less contaminated, Dee estuary. Flounder breed offshore but spend a lot of time in the estuaries, penetrating into ...

Humic substances were extracted from the sediments of two small alpine lakes in the Colorado Front Range and characterized by three-dimensional fluorescence spectroscopy. The fluorescence index (FI), defined as the ratio of fluorescence emitted at 450 nm to that emitted at 500 nm from an excitation wavelength of 370 nm, ...

Marine bivalves are exposed to contaminants via the aqueous phase, sediments and food. Nevertheless, the relative importance of these phases as uptake vectors of contaminants in these marine organisms has not been well studied. Phytoplankton concentrate contaminants from seawater and given their position at the base of most marine food ...

The gastrointestinal absorption factor (f1) for uranium in humans has been determined from a study of 50 volunteers, ingesting uranium at natural levels in drinking water and food. The purpose of the study was to find an appropriate f1 value for humans to use in deriving exposure guidelines for uranium. ...

We examined variation in plasma thyroxine (T4) in juvenile American alligators (Alligator mississippiensis) collected from three sites within the Kissimmee River drainage basin (FL, USA). Based on historical sediment data, Moonshine Bay served as the low contaminant exposure site, Water Conservation Area 3A served as an intermediate contaminant exposure site, ...

Surficial sediments and blue mussels were collected around the perimeter of Halifax Harbour. Samples were analysed for the levels and fingerprint of polycyclic aromatic compounds (PACs). The objective was to explore the relationship between contaminant profiles in sediments and in mussels and to explore the possibility of deducing their sources, ...

Lumbriculus variegatus was used as a bioassay organism to examine the impact of the sediment-associated polycyclic aromatic hydrocarbon (PAH) fluoranthene on behavior, reproduction, and toxicokinetics. The number of worms increased between the beginning and end of the experiment at 59 microg x g(-1) fluoranthene, but at the next higher treatment ...

A year-long research on the Mugil cephalus and M. curema diet was conducted. The food content in the cardiac portion of 192 stomachs revealed a great similarity in both species leading to two conclusions: sediments are their basic food and high levels of benthic diatoms are dominant. A total of ...

The sorption of Si may decisively influence the P dynamics in surface sediment through competitive ligand exchange mechanisms. Many aspects of the process, such as the impact of Si dissolving from diatoms, are both insufficiently known and difficult to monitor by quantitative analyses due to the ubiquitousness of Si in ...

Data on the total concentrations of phosphorus, calcium, iron and organic matter in surface bed-sediments taken from rivers in the Thames catchment (Wey, Blackwater, Thame and Kennet), the River Swale in Yorkshire (data excludes the organic matter content) as well as the headwaters of the Great Ouse, are collated and ...

The variations of concentrations of hexachloro-cyclohexane (HCHs), dichloro diphenyl trichloroethane (DDTs) in surface sediments from the Changjiang Estuary and Zhejiang coastal area suggests that although there is a substantial decrease of these persistent trace compounds since the last two decades, they still presented in recent surface sediments. Their concentration levels ...

Continental margins are important areas to be considered when studying the distributions and depositions of pollutants, both conventional and radioactive. Coastal sediments accumulate most of those contaminants which can be introduced following atmospheric and/or fluvial pathways. Moreover, their residence times within the water column are usually shortened due to their ...

Activity concentrations of 137Cs and 90Sr in samples of vegetation and natural food products collected in the Kola Peninsula in 1998 and 1999 indicate a very slow decrease in contamination levels during the last decade, mainly due to the physical decay of the radionuclides. The activity concentrations of 137Cs in ...

The effect of cadmium on sediment processing by laboratory-cultured specimens of Capitella sp I and Capitella sp B was investigated. Specimens were exposed to 0, 60, 90 and 140 microg Cd g(-1) dry weight sediment for a 10 day period (two census days) to observe effects of cadmium on their ...

Impacts of urban development on a small creek with an on-stream stormwater pond, which was built to mitigate the effects of a 13-ha commercial plaza on creek flows, were assessed by investigations of the creek-pond system hydrology, water and sediment chemistry and toxicity, and benthic communities. The hydrology and conventional ...

The subclass Protobranchia comprises more than 600 species of bivalves that occur throughout the world ocean. Mostly deposit feeders in soft sediments, they are abundant in the deep sea. Apomorphies that unite them as a group include gill structure, hinge conformation, shell microstructure, larval development, foot morphology, respiratory pigments, trophic ...

Cigarette smoking is one of the pathways that might contribute significantly to the increase in the radiation dose reaching man, due to the relatively large concentrations of 210Pb and 210Po found in tobacco leaves. In the present study, the concentrations of these two radionuclides were determined in eight of the ...

To quantify the potential enhancement of naturally-occurring 210Po and 210Pb that may result from the high sulfur-reducing and sulfur-oxidizing regimes associated with hydrothermal vents, sinking particles from both inside and outside vent areas and benthic molluscs grazing on or living near bacterial mats in the vent zone were collected off ...

This paper deals with the distribution and activity intake of 210Po and 210Pb in food, diet, and potable water samples of the Goa region and the estimated committed effective dose due to ingestion of these radionuclides. The activity concentrations of 210Po and 210Pb were determined in about 30 food and ...

The first screening of polybrominated diphenyl ethers (PBDEs) in sediments and blue mussels (Mytilus edulis) collected in the Danish marine and freshwater environment is presented in this work. 10 marine and 6 freshwater sediments, together with blue mussels from 15 locations were analysed for PBDEs. The sum of 5 PBDE ...

Benthic annelid communities were studied during a one-year period (August/95 to July/96) in two sectors of the beaches Engenho d'Agua and São Francisco, São Sebastião Channel (São Paulo, Brazil), where the substrate is composed by a mixture of sand and rock fragments. Abiotic parameters such as salinity of interstitial water ...

The impact on sediment pollution of environmentally sensitive harvesting of a 15 ha plot (20% of the catchment area) of mature coniferous plantation forest in the 0.89 km2 Afon Tanllwyth catchment, Plynlimon, was investigated for 12 months before harvesting began and a further 18 months after. The results revealed: (a) ...

Primitive ornithomimids, a ubiquitous group of specialized Cretaceous dinosaurs nested within a clade of predominantly carnivorous theropods, are known to have had teeth, whereas derived ornithomimids had an edentulous beak, which has prompted speculation about their dietary habits. Here we describe two new ornithomimid specimens in which soft-tissue structures of ...

Effects of 2,4,5-trichlorophenol (TCP) on life-cycle traits of the midge Chironomus riparius and the ability of the midge to evolve tolerance to TCP were assessed using a reference group and a group preexposed to TCP during three generations, both originating from the same laboratory culture. F1 larvae of these groups ...

To understand the effects of diffuse pollution information on the source of pollutants, quantities in transport, mode of transport, transient nature of the pollution event, and most importantly, a consideration of remediation efforts need to be known. For example, water quality research in the Yazoo Basin uplands in Mississippi has ...

Activity concentration of the uranium and thorium series radionuclides was determined in foodstuffs and drinking water in central Poland. Annual and daily intake for the adult population was estimated from the concentrations determined and average annual consumption of food and water. The daily intakes (in mBq) were 22.1 (238U), 26.5 ...

Linear alkylbenzenes (LABs) were used to assess the fates of hydrophobic organic compounds (HOCs) released to a large urban harbor and the adjoining offshore waters. We found that particulate concentrations of the individual C12 LAB isomers in 1996 summertime surface waters decreased from 1 pM in Boston Harbor to 20-200 ...

The impact of soil filtered runoff from a section of the M25 outer London motorway (constructed in 1981) on a pond, wetland and stream in a nature reserve was investigated by monitoring water, sediment. The tissues of the emergent plants Typha latifolia and Glyceria maxima collected from the pond were ...

The present study summarizes the published results of the studies of the Environmental Radioactivity Laboratory on the radiological impact in Greece of the Chernobyl nuclear accident. Some unpublished data from personal communications also have been used to present the time evolution of the studies. The radiological impact in Greece of ...

Distribution of one of the natural radionuclides 210Po activity in food of plant origin such as cereals, pulses, vegetables and food of animal origin such fish, crab, prawn, chicken, egg etc. were determined in and around Kalpakkam upto a distance of 32 km radius. The general range of 210Po activity ...

Enrichments of alkane-degrading microorganisms were established under sulfate-reducing, denitrifying, iron-reducing, and methanogenic conditions using an estuarine sediment. The sulfate-reducing and denitrifying enrichments mineralized [1-14C]hexadecane to 14CO2. Degradation was coupled to sulfate reduction and denitrification, as indicated by the ratios of hexadecane degraded to the electron acceptors reduced. Dependence of hexadecane ...

Polyclonal antibodies against hydrolyzed fumonisin B1 (HFB1) were prepared by immunization of rabbits with a keyhole limpet hemocyanin conjugate coupled by glutaraldehyde. Sensitivity and specificity of these antibodies were tested in a direct competitive enzyme-linked immunosorbent assay (ELISA), in which a HFB1-horseradish peroxidase conjugate prepared by reductive alkylation served as ...

Sorption and diffusion are important processes for the transport of radionuclides through buffer materials such as bentonite. In this study, the sorption and diffusion behaviors of Cs and Sr on Jih-Hsing bentonite are investigated using batch and through-diffusion techniques. The distribution coefficients (Kds) of Cs and Sr from batch experiments ...

Silver (Ag) is discharged in wastewater effluents and is also a component in a proposed secondary water disinfectant. A steady-state model was developed to simulate bioaccumulation in aquatic biota and assess ecological and human health risks. Trophic levels included phytoplankton, invertebrates, brown trout, and common carp. Uptake routes included water, ...

In a large area around the former open-pit lignite mines near Bitterfeld, Germany, groundwater taken from wells was analyzed for the major cations, anions, and trace elements. Quaternary and Tertiary sediments were collected from aquifers exposed on the sides of the pits and from boreholes outside the mines and analyzed ...

Cerro Negro bitumen, separated from an Orimulsion sample, was incubated for up to 120 days with sediments collected at a petroleum-impacted site in Tampa Bay, Florida. Biodegradation conditions were optimized by increasing bitumen surface area, continuous agitation on a shaker apparatus, use of a complete growth medium, and maintenance at ...

Monitoring the estuaries of the Atlantic and Gulf of Mexico coastlines of the United States from Cape Cod, Massachusetts, to Brownsville, Texas, was performed annually from 1990 through 1997 to assess ecological conditions on a regional basis for four biogeographic provinces. These province estimates--Virginian, Carolinian, West Indian, and Louisianian Provinces--are ...

Rural settlements located in areas of the Russian Federation contaminated after the Chernobyl accident and exceeding an annual dose of 1 mSv a-1 have been classified according to 137Cs contamination density, internal dose and the neighbourhood of forests. It has been shown that, with the exception of the most contaminated ...

Water and sediment samples were collected from streams in Spearfish Creek, Whitewood Creek, and Bear Butte Creek watersheds in the Black Hills, SD, an area impacted by gold mining operations. Arsenic concentrations that exceeded the U.S. Environmental Protection Agency's Maximum Concentration Limit of 50 microg/L for drinking water were found ...

Herbicides may leach from agricultural fields into ground water feeding adjacent wetlands. However, only little is known of the fate of herbicides in wetland areas. The purpose of the study was to examine the potential of a riparian fen to mineralize herbides that could leach from an adjacent catchment area. ...

The bioaccumulation of inorganic mercury (HgI) and monomethylmercury (MMHg) by benthic organisms and subsequent trophic transfer couples the benthic and pelagic realms of aquatic systems and provides a mechanism for transfer of sedimentary contaminants to aquatic food chains. Experiments were performed to investigate the bioavailability and bioaccumulation of particle-associated HgI ...

Habit surveys were carried out around four licensed nuclear sites to identify people who collect foodstuffs from the wild (so-called 'free foods'). In total, around 800 collectors were readily identified, most of whom collected more than one free food. The data indicated that estimates of higher than average doses could ...

Clay slurries, mixed in seawater, were deposited on intertidal mudflats in two contrasting estuaries in an experiment designed to evaluate the potential impact of soil erosion from adjacent urban developments on the biodiversity of the benthic communities, and the subsequent recovery mechanisms. Profiles of the natural abundance of stable isotopes ...

Environmental effects of dredging events have been uncommonly reported for shallow, residential estuaries characteristic of the Gulf of Mexico region. The objective of this study was to determine the impact of hydraulic dredging on an urbanized estuary. Physicochemical quality, benthic community composition, whole sediment toxicity, periphytic algal community composition and ...

The reindeer-herding Southern Saamis, from Central Norway, were the population group exposed to the highest levels of radioactivity in Norway, following the Chernobyl accident. Radiocesium whole-body contents and dietary habits have been investigated regularly in this population group since 1987. Meat of semi-domesticated reindeer is important in their diet, and ...